Usually, when people think of bearing materials the first option they will imagine is stainless steel. While this is certainly a common material, there are a range of other choices, each with their own unique advantages and limitations. Depending on application type, bearing experts may advise on a number of materials, and today we’ll take a look at some plastic and non-metallic bearing varieties.
Plastic materials are sometimes used for bearing cages. The most common is molded nylon plastic but molded acetal (POM) is also used. Other polymers are used in special bearing designs where specific performance requirements such as high speed, or low torque or low noise are identified.
Cages made from phenolic (phenol-formaldehyde) materials are most common in high speed ball bearings used in machine tool equipment spindles. The phenolic cages are lightweight and have high strength. The cost of processing this material has led to an increase use of plastics in its place.
The most common seal material is nitrile rubber or Buna rubber. It has good mechanical properties, can be used across a wide temperature range, is resistant to many chemicals and is low in cost. Materials such as Viton and Silicone are expensive elastomers and they’re usually used when an application requires their unique properties.
Bearings made with ceramic materials fall into a specialty niche in the bearing industry. The most common arrangement is a hybrid bearing, usually with stainless steel rings and ceramic balls. The most common ceramic material used is silicon nitride. Balls made from this material are hard, up to Rc78, and have a very smooth surface. Hybrid bearings are more expensive than all stainless steel bearings.
If you need assistance with selecting the appropriate bearing material or have questions about plastic or ceramic bearings, our team of bearing experts provide engineering consulting and design, contact us here to get in touch with them.